I completed this achievement on my character Uderia in January. I logged onto one of my Alts Shadowalk who has completed House Vahla achievement and has 50k faction. I am not getting the currency item to unlock the offhand weapon on this alt character. Both toons are on Halls of Fate.
In order to unlock the one-handed weapon you need on the twink all three faction too. This also turns on the orange runes with Free that you have soldered on your main char for example.
They made a change on Tuesday to this - ITEMS The set of Jade offhand items purchased from Amarat the Procurer now have reduced purchase restrictions for alts. If any character on your account has completed the Destiny in the Planes of Prophecy achievement, any other character will only need to complete a single faction quest line from Vahla, Yrzu, or Pakiat in order to purchase these items. The character who completed the original achievement will need to be logged in once in order to grant the account flag for this change. Caith, Tuesday at 2:30 PMReport